LXR linux/drivers/w1/slaves/w1

   1/*
   2 * w1_ds2413.c - w1 family 3a (DS2413) driver
   3 * based on w1_ds2408.c by Jean-Francois Dagenais <dagenaisj@sonatest.com>
   4 *
   5 * Copyright (c) 2013 Mariusz Bialonczyk <manio@skyboo.net>
   6 *
   7 * This source code is licensed under the GNU General Public License,
   8 * Version 2. See the file COPYING for more details.
   9 */
  10
  11#include <linux/kernel.h>
  12#include <linux/module.h>
  13#include <linux/moduleparam.h>
  14#include <linux/device.h>
  15#include <linux/types.h>
  16#include <linux/delay.h>
  17#include <linux/slab.h>
  18
  19#include "../w1.h"
  20#include "../w1_int.h"
  21#include "../w1_family.h"
  22
  23MODULE_LICENSE("GPL");
  24MODULE_AUTHOR("Mariusz Bialonczyk <manio@skyboo.net>");
  25MODULE_DESCRIPTION("w1 family 3a driver for DS2413 2 Pin IO");
  26MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS2413));
  27
  28#define W1_F3A_RETRIES                     3
  29#define W1_F3A_FUNC_PIO_ACCESS_READ        0xF5
  30#define W1_F3A_FUNC_PIO_ACCESS_WRITE       0x5A
  31#define W1_F3A_SUCCESS_CONFIRM_BYTE        0xAA
  32
  33static ssize_t state_read(struct file *filp, struct kobject *kobj,
  34                          struct bin_attribute *bin_attr, char *buf, loff_t off,
  35                          size_t count)
  36{
  37        struct w1_slave *sl = kobj_to_w1_slave(kobj);
  38        dev_dbg(&sl->dev,
  39                "Reading %s kobj: %p, off: %0#10x, count: %zu, buff addr: %p",
  40                bin_attr->attr.name, kobj, (unsigned int)off, count, buf);
  41
  42        if (off != 0)
  43                return 0;
  44        if (!buf)
  45                return -EINVAL;
  46
  47        mutex_lock(&sl->master->bus_mutex);
  48        dev_dbg(&sl->dev, "mutex locked");
  49
  50        if (w1_reset_select_slave(sl)) {
  51                mutex_unlock(&sl->master->bus_mutex);
  52                return -EIO;
  53        }
  54
  55        w1_write_8(sl->master, W1_F3A_FUNC_PIO_ACCESS_READ);
  56        *buf = w1_read_8(sl->master);
  57
  58        mutex_unlock(&sl->master->bus_mutex);
  59        dev_dbg(&sl->dev, "mutex unlocked");
  60
  61        /* check for correct complement */
  62        if ((*buf & 0x0F) != ((~*buf >> 4) & 0x0F))
  63                return -EIO;
  64        else
  65                return 1;
  66}
  67
  68static BIN_ATTR_RO(state, 1);
  69
  70static ssize_t output_write(struct file *filp, struct kobject *kobj,
  71                            struct bin_attribute *bin_attr, char *buf,
  72                            loff_t off, size_t count)
  73{
  74        struct w1_slave *sl = kobj_to_w1_slave(kobj);
  75        u8 w1_buf[3];
  76        unsigned int retries = W1_F3A_RETRIES;
  77
  78        if (count != 1 || off != 0)
  79                return -EFAULT;
  80
  81        dev_dbg(&sl->dev, "locking mutex for write_output");
  82        mutex_lock(&sl->master->bus_mutex);
  83        dev_dbg(&sl->dev, "mutex locked");
  84
  85        if (w1_reset_select_slave(sl))
  86                goto error;
  87
  88        /* according to the DS2413 datasheet the most significant 6 bits
  89           should be set to "1"s, so do it now */
  90        *buf = *buf | 0xFC;
  91
  92        while (retries--) {
  93                w1_buf[0] = W1_F3A_FUNC_PIO_ACCESS_WRITE;
  94                w1_buf[1] = *buf;
  95                w1_buf[2] = ~(*buf);
  96                w1_write_block(sl->master, w1_buf, 3);
  97
  98                if (w1_read_8(sl->master) == W1_F3A_SUCCESS_CONFIRM_BYTE) {
  99                        mutex_unlock(&sl->master->bus_mutex);
 100                        dev_dbg(&sl->dev, "mutex unlocked, retries:%d", retries);
 101                        return 1;
 102                }
 103                if (w1_reset_resume_command(sl->master))
 104                        goto error;
 105        }
 106
 107error:
 108        mutex_unlock(&sl->master->bus_mutex);
 109        dev_dbg(&sl->dev, "mutex unlocked in error, retries:%d", retries);
 110        return -EIO;
 111}
 112
 113static BIN_ATTR(output, S_IRUGO | S_IWUSR | S_IWGRP, NULL, output_write, 1);
 114
 115static struct bin_attribute *w1_f3a_bin_attrs[] = {
 116        &bin_attr_state,
 117        &bin_attr_output,
 118        NULL,
 119};
 120
 121static const struct attribute_group w1_f3a_group = {
 122        .bin_attrs = w1_f3a_bin_attrs,
 123};
 124
 125static const struct attribute_group *w1_f3a_groups[] = {
 126        &w1_f3a_group,
 127        NULL,
 128};
 129
 130static struct w1_family_ops w1_f3a_fops = {
 131        .groups         = w1_f3a_groups,
 132};
 133
 134static struct w1_family w1_family_3a = {
 135        .fid = W1_FAMILY_DS2413,
 136        .fops = &w1_f3a_fops,
 137};
 138
 139static int __init w1_f3a_init(void)
 140{
 141        return w1_register_family(&w1_family_3a);
 142}
 143
 144static void __exit w1_f3a_exit(void)
 145{
 146        w1_unregister_family(&w1_family_3a);
 147}
 148
 149module_init(w1_f3a_init);
 150module_exit(w1_f3a_exit);
 151